Pat wings completely dry with paper towels, removing as much surface moisture as possible. In a large bowl, toss wings with baking powder, salt, pepper, garlic powder, and smoked paprika until evenly coated. Let rest 10 to 15 minutes at room temperature while preparing the grill.

Set up grill for two-zone cooking. For gas grills, light burners on one side only and set to medium-high, leaving the other side off. For charcoal grills, pile all hot coals on one side of the grill, leaving the other side empty. Aim for grill temperature of 375°F to 400°F on the indirect side. Oil the cooking grate on the indirect side using tongs and an oil-soaked paper towel.

While grill heats, make the honey garlic sauce on the stovetop. Combine honey, soy sauce, garlic, vinegar, butter, sesame oil, and red pepper flakes in a saucepan over medium heat. Simmer 5 to 7 minutes, stirring frequently, until sauce thickens to a syrupy consistency. For extra thickness, stir in cornstarch slurry and cook 30 to 60 seconds more. Keep warm on low heat.

Arrange seasoned wings on the indirect heat side of the grill in a single layer with space between each piece. Close lid and cook for 15 minutes. Open grill, flip all wings with tongs, close lid, and cook 15 to 20 minutes more until wings reach 165°F to 170°F internal temperature and skin looks golden and dry.

Move wings to the direct heat side of the grill. Cook 2 to 3 minutes per side, watching constantly and flipping as needed to prevent burning, until skin is deeply golden brown with visible grill marks and internal temperature reaches 175°F to 185°F. Total cooking time is 35 to 40 minutes from start to finish.

Transfer hot wings immediately to a large bowl. Pour warm honey garlic sauce over wings and toss thoroughly with tongs until every wing is evenly coated and glossy. Let rest 1 to 2 minutes before transferring to serving platter. Garnish with toasted sesame seeds or sliced green onions if desired. Serve immediately while hot and crispy.